Lens barrel and lens support structure

ABSTRACT

A lens barrel is provided with which manufacturing costs can be reduced. The lens barrel ( 3 ) has a first lens group (G 1 ), a second lens group (G 2 ), a third lens group (G 3 ), a first support frame ( 10 ) that supports the first lens group (G 1 ), a second support frame ( 20 ) that supports the second lens group (G 2 ), a third support frame ( 30 ) that supports the third lens group (G 3 ), a first driving unit ( 50 ), a second driving unit ( 60 ), and a shutter unit ( 29 ) that is fixed to the second support frame ( 20 ). The first lens group (G 1 ) has an overall negative refractive power, and includes a prism (PR). The second support frame ( 20 ) is driven along a second optical axis (A 2 ) by the first driving unit ( 50 ). The third support frame ( 30 ) is driven along the second optical axis (A 2 ) by the second driving unit ( 60 ).

TECHNICAL FIELD

The present invention relates to a lens barrel having a bending opticalsystem.

BACKGROUND ART

Digital cameras that make use of imaging elements have become verypopular in recent years. With digital camera, there has been a need notonly for a greater number of pixels in the imaging elements, but alsofor higher performance of the lens barrel, which forms an optical imageon the imaging elements. More specifically, there is a need for a lensbarrel equipped with a higher-power zoom lens system.

Meanwhile, in the field of digital camera, the main body needs to bemade smaller in order to make the product more portable. There istherefore a need for a more compact imaging device equipped with a lensbarrel and an imaging element, which should contribute greatly to thegoal of obtaining a smaller main body. To reduce the size of an imagingdevice, a so-called bending optical system has been proposed in whichthe optical path is bent along the zoom lens system (see PatentCitations 1 to 4, for example).

Patent Citation 1: Japanese Patent No. 3,925,457

Patent Citation 2: Japanese Laid-Open Patent Application 2007-17957

Patent Citation 3: Japanese Laid-Open Patent Application 2007-271649

Patent Citation 4: Japanese Laid-Open Patent Application 2005-351932

DISCLOSURE OF INVENTION

An imaging optical system usually has a plurality of lens groups.Whether the refractive power of the first lens group that takes in lightfrom a subject is positive or negative affects how small the lens barrelcan be made, the magnification ratio of the optical system, and soforth.

For instance, if the first lens group has a positive refractive power(in the case of an imaging optical system that is called a positive leadtype), it is easy to attain a high magnification ratio, but the quantityof lenses is greater, which is disadvantageous in terms of making thelens barrel smaller.

On the other hand, if the first lens group has a negative refractivepower (in the case of an imaging optical system that is called anegative lead type), it is more difficult to attain a high magnificationratio than with a positive lead type, but there are fewer lenses, whichis advantageous in terms of making the lens barrel smaller, and is alsosuited to achieving a wider angle.

Thus, when the first lens group has a negative refractive power, it iseasier to obtain a lens barrel that is compact and has a wider angle.

Nevertheless, with a negative lead type of imaging optical system, asecond lens group and third lens group having positive refractive powermust be movably provided behind the first lens group, so an apertureunit and a shutter unit must be moved according to the movement of theselens groups. Accordingly, a mechanism for driving these units isnecessary, which increases the number of parts required, and this candrive up the manufacturing cost.

It is a first object of the present invention to provide a lens barrelwith which manufacturing costs can be reduced.

Also, an aperture unit has a plurality of aperture blades, but sincethere needs to be a certain amount of distance from the lenses to theaperture blades, it is more difficult to reduce the size of a lenssupport structure that includes lenses and an aperture unit.

It is a second object of the present invention to provide a lens supportstructure whose size can be reduced.

A lens barrel according to a first aspect is a lens barrel for formingan optical image of a subject, comprising a first lens group, a secondlens group, a third lens group, a first support frame, a first supportmechanism, a first driving unit, a luminous energy adjusting unit, andan optical path blocking unit. The first lens group is a lens group thattakes in a light beam coming from the subject along a first optical axisfrom, and has a bending optical element that reflects a light beamincident along the first optical axis along a second optical axis thatintersects the first optical axis. The second lens group takes in alight beam that has passed through the first lens group. The third lensgroup takes in a light beam that has passed through the second lensgroup. The first support frame supports the first lens group. The firstsupport mechanism is a mechanism that supports the second lens groupmovably with respect to the first lens group along the second opticalaxis, and has a second support frame that supports the second lensgroup. The first driving unit imparts a drive force to the secondsupport frame so that the second lens group moves along the secondoptical axis. The luminous energy adjusting unit is a mechanism foradjusting the amount of light passing through the second lens group orthe amount of light emitted from the second lens group, and is fixed tothe second support frame. The optical path blocking unit is a mechanismfor opening or blocking the optical path along the second optical axis,and is fixed to the second support frame.

With this lens barrel, since the luminous energy adjusting unit and theoptical path blocking unit are fixed to the second support frame, thefirst driving unit can be shared by the second support frame, theluminous energy adjusting unit, and the optical path blocking unit, andthere is no need to provide a separate driving unit for the luminousenergy adjusting unit and the optical path blocking unit. Thissimplifies the constitution of the lens barrel, and reduces itsmanufacturing costs.

A lens barrel according to a second aspect is the lens barrel accordingto the first aspect, wherein the luminous energy adjusting unit isdisposed on the first lens group side of the second support frame alongthe second optical axis.

A lens barrel according to a third aspect is the lens barrel accordingto the first or second aspect, wherein the optical path blocking unit isdisposed on the opposite side of the second support frame from the firstlens group side along the second optical axis.

A lens barrel according to a fourth aspect is the lens barrel accordingto any one of the first to third aspects, wherein the optical pathblocking unit has an optical path blocking mechanism provided so as toallow the optical path to be opened and blocked along the second opticalaxis, and a blocking drive motor that drives the optical path blockingmechanism. The blocking drive motor is disposed more to the first lensgroup side than the optical path blocking mechanism along the secondoptical axis.

A lens barrel according to a fifth aspect is the lens barrel accordingto any one of the first to fourth aspects, further comprising a mainbody frame to which the first support mechanism is provided. Theluminous energy adjusting unit has a luminous energy adjusting mechanismwith which the aperture can be adjusted by utilizing a rotational forcearound the second optical axis, and a transmission member provided so asto be able to transmit the rotational force to the luminous energyadjusting mechanism. The main body frame has a guide portion thatconverts the linear motion of the second support frame along the secondoptical axis with respect to the main body frame into rotary motion ofthe transmission member around the second optical axis.

A lens barrel according to a sixth aspect is the lens barrel accordingto the fifth aspect, wherein the transmission member extends from theluminous energy adjusting mechanism in a direction perpendicular to thesecond optical axis. The guide portion has a guide groove into which thetransmission member is inserted, and which is inclined with respect to adirection along the second optical axis.

A lens barrel according to a seventh aspect is the lens barrel accordingto any one of the first to sixth aspects, wherein the first lens grouphas an overall negative refractive power.

A lens support structure according to an eighth aspect comprises a lenshaving a convex face, a lens support frame that supports the lens, andan aperture member that is fixed to the lens support frame. At leastpart of the convex face of the lens is disposed within the opening ofthe aperture member along the optical axis of the lens.

With this lens support structure, since at least part of the convex faceof the lens is disposed within the opening of the aperture member alongthe optical axis of the lens, the aperture member can be disposed closerto the lens. This shortens the overall length of the aperture member andthe lens along the optical axis, and affords a more compact size.

A lens support structure according to a ninth aspect is the lens supportstructure according to the eighth aspect, wherein the aperture member isprovided so that its position with respect to the lens does not change.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a simplified perspective view of a digital camera;

FIG. 2 is a simplified perspective view of a digital camera;

FIG. 3 is a simplified perspective view of a lens barrel;

FIG. 4 is a simplified perspective view of a lens barrel;

FIG. 5 is a front view of a lens barrel;

FIG. 6 is a rear view of a lens barrel;

FIG. 7 is a side view of a lens barrel;

FIG. 8 is a side view of a lens barrel;

FIG. 9 is a diagram of the configuration of an imaging optical system;

FIG. 10 is a simplified cross section of a lens barrel;

FIG. 11 is a simplified cross section of a lens barrel;

FIG. 12 is a cross section of a first lens group and the surroundingarea;

FIG. 13 is a perspective view of a second support frame;

FIGS. 14A and 14B are cross sections of a second lens group and a secondsupport frame;

FIGS. 15A and 15B are plan views of an aperture unit;

FIG. 16 is a simplified plan view of a lens barrel;

FIG. 17 is a simplified plan view of a lens barrel;

FIG. 18 is a simplified plan view of a lens barrel;

FIG. 19 is a simplified plan view of a lens barrel;

FIG. 20 is a simplified plan view of a lens barrel; and

FIG. 21 is a simplified plan view of a lens barrel.

EXPLANATION OF REFERENCE

1 digital camera

2 camera body

3 lens barrel

10 first support frame

12 forward portion

12 a first protrusion

20 second support frame

21 second support frame main body

22 aperture unit (luminous energy adjusting unit)

22 a aperture mechanism (aperture member)

23 first guide portion

24 second guide portion

25 first drive member

26 neutral density filter (optical element)

27 shutter drive motor (blocking drive motor)

28 filter drive motor (element drive motor)

29 shutter unit (optical path blocking unit)

30 third support frame

40 lens drive device (optical element drive device)

41 fourth support frame

50 first driving unit

51 first drive motor

52 first lead screw (first drive shaft)

53 first frame

60 second driving unit

61 second drive motor

62 second lead screw (second drive shaft)

63 second frame

70 main body frame

71 forward plate

72 guide portion

72 a guide groove

G1 first lens group

G2 second lens group

G3 third lens group

G4 fourth lens group

BEST MODE FOR CARRYING OUT THE INVENTION

Overview of Digital Camera

A digital camera 1 according to an embodiment of the present inventionwill now be described through reference to FIGS. 1 and 2. FIGS. 1 and 2are simplified perspective views of the digital camera 1.

The digital camera 1 is a camera for capturing an image of a subject,and employs a bending optical system for boosting magnification andreducing the overall size.

In the following description, the six sides of the digital camera 1 aredefined as follows.

The side facing the subject when an image is being captured by thedigital camera 1 is called the front face of a camera main body 2, andthe face on the opposite side is called the rear face. When an image iscaptured such that the top and bottom in the vertical direction of thesubject match up with the top and bottom in the short-side direction ofthe rectangular image being captured by the digital camera 1 (the aspectratio (the ratio of long to short sides) is generally 3:2, 4:3, 16:9,etc.), the side facing upward in the vertical direction is called thetop face, and the opposite side is called the bottom face. Further, whenthe an image is captured such that the top and bottom in the verticaldirection of the subject match up with the top and bottom in theshort-side direction of the rectangular image being captured by thedigital camera 1, the side that is on the left when viewed from thesubject side is called the left face, and the opposite side is calledthe right face. The above definitions are not intended to limit theusage orientation of the digital camera 1.

Based on the above definitions, FIG. 1 is a perspective viewillustrating the front face, top face, and right face.

The same definitions apply not only to the six sides of the digitalcamera 1, but also to the six sides of the various constituent membersdisposed on the digital camera 1. That is, the above definitions applyto the six sides of the various constituent members when they have beendisposed in the digital camera 1.

As shown in FIG. 1, a three-dimensional perpendicular coordinate systemis defined, having a Y axis perpendicular to the front face of thecamera main body 2. Based on this definition, the direction facing thefront face side from the rear face side is called the Y axis positivedirection, the direction facing the left face side from the right faceside is called the X axis positive side, and the direction facing thetop face side from the bottom face side and perpendicular to the X and Yaxes is called the Z axis positive direction.

The drawings will be described below using this XYZ coordinate system asa reference. That is, the X axis positive side, the Y axis positivedirection, and the Z axis positive direction in the drawings each referto the same respective direction.

Overall Configuration of Digital Camera

As shown in FIGS. 1 and 2, the digital camera 1 mainly includes a cameramain body 2 that houses various units, a lens barrel 3 for forming anoptical image of a subject, and an imaging unit 90. The imaging unit 90has an imaging element 91 for converting an optical image into an imagesignal, and examples of the imaging element 91 include a CCD (chargecoupled device) and a CMOS (complementary metal-oxide semiconductor)sensor.

A release button 4, a control dial 5, a power switch 6, and a zoomadjusting lever 7 are provided to the top face of the camera main body 2so that the user can control the imaging operation, etc. The releasebutton 4 is used by the user to input the exposure timing. The controldial 5 is used by the user to make various settings related to imagingoperation. The power switch 6 is used by the user to turn the digitalcamera 1 on or off. The zoom adjusting lever 7 is used by the user toadjust the zoom magnification, and is able to rotate around the releasebutton 4 within a specific angular range. A liquid crystal monitor 8that displays images captured by the imaging element 91 is arranged onthe rear face of the camera main body 2.

Configuration of Lens Barrel

The configuration of the lens barrel 3 will be described throughreference to FIGS. 3 to 21. FIGS. 3 and 4 are simplified perspectiveviews of the lens barrel 3. FIG. 5 is a front view of the lens barrel 3.FIG. 6 is a rear view of the lens barrel 3. FIGS. 7 and 8 are side viewsof the lens barrel 3. In FIGS. 5 to 8, part of a main body frame 70 isomitted so that the internal structure of the lens barrel 3 can be seen.

FIG. 9 is a diagram of the configuration of an imaging optical system.FIG. 9 shows a wide angle state. FIGS. 10 and 11 are simplified crosssections of the lens barrel 3. FIG. 10 shows the wide angle state, andFIG. 11 shows a telephoto state. FIG. 12 is a cross section of a firstlens group G1 and the surrounding area. FIG. 13 is a perspective view ofa second support frame 20. FIGS. 14A and 14B are cross sections of asecond lens group G2 and the second support frame 20. In FIG. 14A, aseventh lens L7 is omitted. FIGS. 15A and 15B are plan views of anaperture unit 22. FIG. 15A shows a stopped state, and FIG. 15B shows anopen state.

FIGS. 16 to 21 are simplified plan views of the lens barrel 3 as viewedin the Z axial direction. In FIG. 16, a part of the main body frame 70is omitted. In FIG. 17, a first driving unit 50 and a second drivingunit 60 are omitted. In FIG. 18, the second support frame 20 is omitted.In FIG. 19, a shutter unit 29 is omitted. FIG. 20 is a simplified planview of a lens driving device 40. In FIG. 21, a first yoke 46 and asecond yoke 47 are omitted.

As shown in FIGS. 3 to 8, the lens barrel 3 has the imaging opticalsystem (which employs a bending optical system for bending the opticalpath), a first support frame 10, the second support frame 20, a thirdsupport frame 30, the first driving unit 50, the second driving unit 60,the main body frame 70, the aperture unit 22, the shutter unit 29, andthe lens driving device 40 (which supports a fourth lens group G4 of theimaging optical system).

(1) Imaging Optical System

As shown in FIG. 9, the imaging optical system has the first lens groupG1, the second lens group G2, a third lens group G3, and the fourth lensgroup G4.

The first lens group G1 is a lens group that overall has negativerefractive power, and is provided so as to take in the light beamincident along a first optical axis A1 from the subject. Morespecifically, the first lens group G1 is supported by the first supportframe 10, and has a first lens L1, a prism PR (an example of a bendingoptical element), a second lens L2, and a third lens L3. The first lensL1 has the first optical axis A1, and the second lens L2 and third lensL3 have a second optical axis A2 that is substantially perpendicular tothe first optical axis A1. The prism PR is an internal reflection prism,for example, and has a reflection face PR1 that reflects the light beamincident along the first optical axis A1, in a direction along thesecond optical axis A2.

The second lens group G2 is a lens group that overall has positiverefractive power, and takes in light that has been bent by the firstlens group G1. More specifically, the second lens group G2 is supportedby the second support frame 20, and has a fourth lens L4, a fifth lensL5, a sixth lens L6, and a seventh lens L7.

The fourth to seventh lenses L4 to L7 are supported by the secondsupport frame 20 so that the optical axes of the fourth to seventhlenses L4 to L7 coincide with the second optical axis A2. The secondsupport frame 20 is provided so as to be capable of moving in adirection along the second optical axis A2 with respect to the main bodyframe 70, and the fourth to seventh lenses L4 to L7 move integrally in adirection along the second optical axis A2 from the wide angle endtoward the telephoto end. Therefore, the second lens group G2 canfunction as a variable power group for varying the power of the imagingoptical system.

The third lens group G3 has an eighth lens L8 that takes in a light beamthat has passed through the second lens group G2, and has positiverefractive power. The eighth lens L8 is supported by the third supportframe 30 so that the optical axis of the eighth lens L8 coincides withthe second optical axis A2. The third support frame 30 is provided so asto be capable of moving in a direction along the second optical axis A2with respect to the main body frame 70, and the eighth lens L8 moves ina direction along the second optical axis A2 from the wide angle endtoward the telephoto end. Therefore, the eighth lens L8 can function asa focusing lens.

The fourth lens group G4 has a ninth lens L9 that takes in a light beamthat has passed through the third lens group G3, and functions as animage blur correcting lens. The ninth lens L9 is supported by the lensdriving device 40 (discussed below; an example of the third drivingunit) so as to be capable of moving within a plane that is perpendicularto the second optical axis A2. The optical axis of the fourth lens groupG4 faces in substantially the same direction as the second optical axisA2. The fourth lens group G4 does not move in a direction along thesecond optical axis A2.

The aperture stop of this imaging optical system is always located onthe first lens group G1 of the second lens group G2, so the position ofthis aperture stop moves along the second optical axis A2, from the wideangle end toward the telephoto end, along with the second lens group G2and the third lens group G3. The aperture unit 22 (a luminous energyadjusting unit) is disposed at the location of this aperture stop. Theaperture unit 22 is fixed to the second support frame 20, and movesalong with the second lens group G2 in a direction along the secondoptical axis A2. The aperture unit 22 will be discussed below.

(2) First Support Frame

The imaging optical system described above is supported by varioussupport frames. More specifically, as shown in FIGS. 5 to 8, the firstlens group G1 is fixed by adhesive bonding, for example, to the firstsupport frame 10. The first support frame 10 is fixed to the end of themain body frame 70 on the Z axis positive direction side. The firstsupport frame 10 has a first support frame main body 11 and a forwardportion 12. As shown in FIG. 12, the prism PR, the second lens L2, andthe third lens L3 of the first lens group G1 are fixed to the firstsupport frame main body 11. The first lens L1 is fixed to the forwardportion 12.

As shown in FIG. 5, part of the main body frame 70 and the first supportframe 10 overlap when viewed in a direction along the first optical axisA1. More specifically, as shown in FIG. 12, the main body frame 70 has aforward plate 71 that is disposed on the Y axis positive direction sideof the second lens group G2 and the third lens group G3 and extends inthe Z axial direction. The forward portion 12 of the first support frame10 is disposed on the Z axis positive direction side of the forwardplate 71.

The forward portion 12 has a first protrusion 12 a that protrudes in adirection along the second optical axis A2, and a second protrusion 12 bthat protrudes in a direction along the first optical axis A1. The firstprotrusion 12 a is disposed on the Y axis negative direction side of theforward plate 71. The forward plate 71 has a recess 71 a that isrecessed on the Z axis negative direction side. The second protrusion 12b is inserted into the recess 71 a.

(3) Second Support Frame

The second lens group G2 is fixed by adhesive bonding, for example, tothe second support frame 20. A first guide shaft 59 and a second guideshaft 69 are fixed to the main body frame 70. The second support frame20 is supported by the first guide shaft 59 and the second guide shaft69 so as to be capable of moving along the second optical axis A2.

More specifically, the second support frame 20 has a second supportframe main body 21 to which the second lens group G2 is fixed, a firstguide portion 23 that slides with the first guide shaft 59, a secondguide portion 24 that slides with the second guide shaft 69, and a firstdrive member 25 that receives the drive force generated by the firstdriving unit 50. The second support frame 20, the first guide shaft 59,and the second guide shaft 69 constitute a first support mechanism 51for movably supporting the second lens group G2. The second supportframe 20 is guided mainly by the first guide shaft 59. The second guideshaft 69 prevents the second support frame 20 from rotating around thefirst guide shaft 59.

As shown in FIG. 13, the second support frame main body 21 iscylindrical in shape, and has an opening 21 a, two first bonding grooves21 b for bonding the fifth lens L5, and two second bonding grooves 21 cfor bonding the seventh lens L7. The first bonding grooves 21 b aredisposed flanking the second optical axis A2. The two second bondinggrooves 21 c are also disposed flanking the second optical axis A2. Thefirst bonding grooves 21 b and second bonding grooves 21 c are disposedalternately at a constant pitch in the circumferential direction.

The first bonding grooves 21 b are formed deeper than the second bondinggrooves 21 c, and as shown in FIG. 14A, they extend in a direction alongthe second optical axis A2 to the outer peripheral side of the fifthlens L5. The outer peripheral face of the fifth lens L5 is mated to theopening 21 a. An annular ridge 21 e is formed on the fourth lens L4 sideof the opening 21 a. The fifth lens L5 comes into contact with theannular ridge 21 e, and this annular ridge 21 e positions the fifth lensL5 with respect to the second support frame 20 in a direction along thesecond optical axis A2. The sixth lens L6 is joined on the seventh lensL7 side of the fifth lens L5. The first bonding grooves 21 b are filledwith an adhesive (not shown), which fixes the fifth lens L5 to thesecond support frame 20.

Meanwhile, the second bonding grooves 21 c are formed shallower than thefirst bonding grooves 21 b, and as shown in FIG. 14B, they do not extendall the way to the outer peripheral side of the fifth lens L5. Theseventh lens L7 comes into contact with an annular face 21 d, and thisannular face 21 d positions the seventh lens L7 with respect to thesecond support frame 20 in a direction along the second optical axis A2.The second bonding grooves 21 c are filled with an adhesive (not shown),and this fixes the seventh lens L7 to the second support frame 20.

(4) First Driving Unit

The second support frame 20 is driven by the first driving unit 50. Morespecifically, the first driving unit 50 has a first drive motor 51, afirst lead screw 52 (an example of a first drive shaft) that isrotationally driven by the first drive motor 51, and a first frame 53that supports the first drive motor 51 and the first lead screw 52.

The first drive member 25 threads onto the first lead screw 52. Thefirst drive member 25 is supported by the second support frame main body21 so as to be rotatable and to move integrally in the axial direction.With this configuration, when the first lead screw 52 turns, the secondsupport frame 20 moves along the second optical axis A2.

(5) Aperture Unit and Shutter Unit

The aperture unit 22 and the shutter unit 29 are fixed to the secondsupport frame 20. The aperture unit 22 is fixed on the first lens groupG1 side of the second support frame 20, and the shutter unit 29 is fixedon the imaging unit 90 side of the second support frame 20 (the oppositeside from the first lens group G1 side).

The aperture unit 22 has an aperture mechanism 22 a (an example of anaperture member) with which the rotational force around the secondoptical axis A2 can be utilized to adjust the aperture, and a drivelever 22 b provided so as to be capable of transmitting rotational forceto the aperture mechanism 22 a. As shown in FIG. 10, part of the convexface L4 a of the fourth lens L4 is disposed within the opening of theaperture mechanism 22 a. That is, when viewed in a direction along thefirst optical axis A1, part of the fourth lens L4 goes inside theaperture unit 22, and part of the fourth lens L4 overlaps the apertureunit 22.

As shown in FIG. 4, the main body frame 70 has a guide portion 72 withwhich the linear motion of the second support frame 20 with respect tothe main body frame 70 in a direction along the second optical axis A2is converted into rotary motion of the drive lever 22 b around thesecond optical axis A2. More specifically, as shown in FIGS. 4, 15A, and15B, the drive lever 22 b extends from the aperture mechanism 22 a in adirection that is perpendicular to the second optical axis A2. FIG. 15Ashows a state in which the aperture unit 22 has been stopped, while FIG.15B shows a state in which the aperture unit 22 has been opened.

The guide portion 72 has a guide groove 72 a into which the drive lever22 b is inserted. The guide groove 72 a slants in a direction along thesecond optical axis A2. When the second support frame 20 moves along thesecond optical axis A2, the drive lever 22 b moves through the guidegroove 72 a, and the drive lever 22 b rotates around the second opticalaxis A2 with respect to the second support frame 20. This allows thedrive of the aperture mechanism 22 a to be performed by the firstdriving unit 50.

The shutter unit 29 has a shutter mechanism 29 a provided so that theoptical path along the second optical axis A2 can be opened or blockedoff, and a shutter drive motor 27 that drives the shutter mechanism 29a. The shutter drive motor 27 is disposed more to the first lens groupG1 side than the shutter mechanism 29 a in a direction along the secondoptical axis A2.

Further, the shutter unit 29 is provided with a neutral density filter26 (an example of an optical element; see FIG. 18) provided so as to becapable of being inserted into the optical path along the second opticalaxis A2 and being retracted from the optical path, and a filter drivemotor 28 (an example of an element drive motor) that drives the neutraldensity filter 26. The filter drive motor 28 is disposed more to thefirst lens group G1 side than the neutral density filter 26 in adirection along the second optical axis A2.

(6) Third Support Frame

As shown in FIGS. 5 to 11, the third lens group G3 is fixed to the thirdsupport frame 30 by adhesive bonding, for example. The third supportframe 30 is supported movably along the second optical axis A2 by thefirst guide shaft 59 and the second guide shaft 69. More specifically,the third support frame 30 has a third support frame main body 31 towhich the third lens group G3 is fixed, a third guide portion 33 thatslides with the second guide shaft 69, a fourth guide portion 34 thatslides with the first guide shaft 59, and a second drive member 35 thatreceives the drive force generated by the second driving unit 60.

The third support frame 30, the first guide shaft 59, and the secondguide shaft 69 constitute a second support mechanism S2 for movablysupporting the third lens group G3. The third support frame 30 is mainlyguided by the second guide shaft 69. The first guide shaft 59 preventsthe third support frame 30 from rotating around the second guide shaft69.

(7) Second Driving Unit

The third support frame 30 is driven by the second driving unit 60. Morespecifically, the second driving unit 60 has a second drive motor 61, asecond lead screw 62 (an example of a second drive shaft) that isrotationally driven by the second drive motor 61, and a second frame 63that supports the second drive motor 61 and the second lead screw 62.The second drive member 35 is threaded onto the second lead screw 62.The second drive member 35 is supported by the third support frame mainbody 31 so as to be rotatable and to move integrally in the axialdirection. With this configuration, when the second lead screw 62 turns,the third support frame 30 moves along the second optical axis A2.

(8) Lens Driving Device

The lens driving device 40 is disposed on the Z axis negative directionside of the main body frame 70, and the fourth lens group G4 issupported by this lens driving device 40 so as to be capable of movingwithin a plane that is perpendicular to the second optical axis A2. Morespecifically, the lens driving device 40 has a base plate 43, a fifthsupport frame 42 that is supported movably in the Y axis direction bythe base plate 43, a fourth support frame 41 that is supported movablyin the X axis direction by the fifth support frame 42, and an electricalboard 48 fixed to the fourth support frame 41. The base plate 43 isfixed to the main body frame 70 by a fixing member (not shown), forexample.

Further, the lens driving device 40 has a first coil C11, a second coilC12, a third coil C20, a first magnet 44, a second magnet 45, a firstyoke 46, and a second yoke 47. The first coil C11 and the second coilC12 are used to drive the fourth support frame 41 in the pitch direction(Y axis direction), and are disposed at the X axial ends of theelectrical board 48 so as to flank the second optical axis A2. The thirdcoil C20 is used to drive the fourth support frame 41 in the yawdirection (X axis direction), and is disposed on the Y axis negativedirection side of the second coil C12.

The first yoke 46 and the second yoke 47 are fixed to the base plate 43.The first magnet 44 is fixed to the first yoke 46 so as to be oppositethe first coil C11 in the Z axis direction, and the second magnet 45 isfixed to the second yoke 47 so as to be opposite the third coil C20 inthe Z axis direction.

The lens driving device 40 has a pitch position sensor D1 and a yawposition sensor D2. The pitch position sensor D1 is used to detect theposition of the fourth support frame 41 in the pitch direction. The yawposition sensor D2 is used to detect the position of the fourth supportframe 41 in the yaw direction. The pitch position sensor D1 and the yawposition sensor D2 allow the position of the fourth support frame 41 tobe detected.

As shown in FIG. 21, the portion of the first magnet 44 corresponding tothe first coil C11 is subjected to dipolar magnetization so as to lineup in the Y axis direction. The portion of the first magnet 44corresponding to the second coil C12 is subjected to dipolarmagnetization so as to line up in the X axis direction. The portion ofthe second magnet 45 corresponding to the second coil C12 and the pitchposition sensor D1 is subjected to dipolar magnetization so as to lineup in the Y axis direction. The portion of the second magnet 45corresponding to the third coil C20 is subjected to dipolarmagnetization so as to line up in the X axis direction.

As discussed above, the first coil C11, the second coil C12, the firstmagnet 44, the second magnet 45, the first yoke 46, and the second yoke47 constitute a pitch driving unit 81 that drives the fourth supportframe 41 in the pitch direction. The third coil C20, the second magnet45, and the second yoke 47 constitute a yaw driving unit 82 that drivesthe fourth support frame 41 in the yaw direction.

Movement Region of Second and Third Support Frames

The region of movement of the second support frame 20 and the thirdsupport frame 30 will now be described.

As shown in FIG. 10, the second support frame 20 moves from the wideangle end to the telephoto end of the imaging optical system, within therange of a first stroke M23, along the second optical axis A2. In FIG.10, the first stroke M23 is shown using the first drive member 25 as areference. If we let a first dimension M22 be the dimension of the firstdrive member 25 in a direction along the second optical axis A2, thenthe region occupied by the first drive member 25 within the range fromthe wide angle end to the telephoto end is a first movement region M21.

Meanwhile, the third support frame 30 moves from the wide angle end tothe telephoto end, within the range of a second stroke M33, along thesecond optical axis A2. In FIG. 10, the second stroke M33 is shown usingthe second drive member 35 as a reference. If we let a second dimensionM32 be the dimension of the second drive member 35 in a direction alongthe second optical axis A2, then the region occupied by the second drivemember 35 within the range from the wide angle end to the telephoto endis a second movement region M31.

It can be seen from FIG. 10 that the first movement region M21 partiallyoverlaps the second movement region M31. Further, the first stroke M23partially overlaps the second stroke M33. As a result, the size of thelens barrel 3 can be reduced in a direction along the second opticalaxis A2.

Features of Layout

The layout of the constituent components of the lens barrel 3 has thefollowing features. Specifically, when viewed in a direction along thesecond optical axis A2, the first driving unit 50 and the second drivingunit 60 are disposed flanking the second optical axis A2. In morespecific terms, as shown in FIGS. 16 to 21, when a first boundary E1 isset extending in the Y axis direction and intersecting the secondoptical axis A2, the first driving unit 50 and the second driving unit60 are disposed on both sides, flanking the first boundary E1. The firstdriving unit 50 is disposed at the end of the lens barrel 3 on the Xaxis positive direction side, and the second driving unit 60 is disposedat the end of the lens barrel 3 on the X axis negative direction side.

When a second boundary E2 is set extending in the X axis direction andintersecting the second optical axis A2, the first driving unit 50 andthe second driving unit 60 are disposed on both sides, flanking thesecond boundary E2. In more specific terms, a first rotational center R1of the first lead screw 52 of the first driving unit 50 is disposed moreto the Y axis positive direction side than the second optical axis A2. Asecond rotational center R2 of the second lead screw 62 of the seconddriving unit 60 is disposed more to the Y axis negative direction sidethan the second optical axis A2. The second optical axis A2 is disposednear or on a line connecting the first rotational center R1 and thesecond rotational center R2. The first guide shaft 59 is disposed nearthe first driving unit 50. The second guide shaft 69 is disposed nearthe second driving unit 60.

Also, the first driving unit 50 and/or the second driving unit 60overlaps the lens driving device 40. In more specific terms, the firstdriving unit 50 overlaps the yaw driving unit 82, and the second drivingunit 60 overlaps the pitch driving unit 81.

Further, as shown in FIGS. 5 and 6, the outer end of the first drivingunit 50 on the opposite side from the second optical axis (morespecifically, a first outer end face 53 a of the first frame 53) isdisposed at substantially the same position (the position in the X axisdirection) as the outer end of the yaw driving unit 82 on the oppositeside from the second optical axis A2.

The outer end of the second driving unit 60 on the opposite side fromthe second optical axis (more specifically, a third outer end face 63 aof the second frame 63) is disposed at substantially the same position(the position in the X axis direction) as the outer end of the pitchdriving unit 81 on the opposite side from the second optical axis A2.

As shown in FIGS. 5 and 6, the first drive motor 51 is disposed closerto the first lens group G1 than the second drive motor 61 in a directionalong the second optical axis A2. The first drive motor 51 is disposedmore to the Z axis positive direction side than the second drive motor61. The first drive motor 51 is disposed to the side in the X axisdirection of the first support frame 10 and the first lens group G1.

As shown in FIGS. 5 to 21, the shutter drive motor 27 and the filterdrive motor 28 are disposed flanking the second optical axis A2. Morespecifically, the first guide shaft 59 and the second guide shaft 69 aredisposed flanking the first boundary E1. When viewed in a directionalong the second optical axis A2, the first guide shaft 59 and thesecond guide shaft 69 are disposed flanking the second optical axis A2.When viewed in a direction along the second optical axis A2, the firstguide shaft 59 is disposed near the filter drive motor 28, and thesecond guide shaft 69 is disposed near the shutter drive motor 27.

To summarize the above layout, the first driving unit 50, the firstguide shaft 59, and the filter drive motor 28 are disposed on the X axisnegative direction side of the first boundary E1, and the second drivingunit 60, the second guide shaft 69, and the shutter drive motor 27 aredisposed on the X axis positive direction side of the first boundary E1.

Also, the first driving unit 50, the first guide shaft 59, and theshutter drive motor 27 are disposed on the Y axis positive directionside of the second boundary E2, and the second driving unit 60, thesecond guide shaft 69, and the filter drive motor 28 are disposed on theY axis negative direction side of the second boundary E2.

Operation of Digital Camera

The operation of the digital camera 1 will be described. The basicoperation of the digital camera 1 will be skipped, since it is nodifferent from the basic operation of a conventional camera.

(1) Zoom Operation During Imaging

With the power on, the imaging optical system is set to the wide angleend (the state shown in FIG. 10), for example. When the zoom adjustinglever 7 is turned to the telephoto side, the second support frame 20 andthe third support frame 30 are driven in a direction along the secondoptical axis A2 by the first driving unit 50 and the second driving unit60 according to the rotational angle and operation time of the zoomadjusting lever 7. More specifically, when the first lead screw 52 isrotationally driven by the first drive motor 51 of the first drivingunit 50, the second support frame 20 moves along the second optical axisA2 to the first lens group G1 side (see FIG. 11, for example). When thesecond lead screw 62 is rotationally driven by the second drive motor 61of the second driving unit 60, the third support frame 30 moves alongthe second optical axis A2 to the first lens group G1 side (see FIG. 11,for example). The second support frame 20 moves linearly from the wideangle end to the telephoto end, but the third support frame 30 turnsback to the imaging unit 90 side midway, and again moves to the firstlens group G1 side.

When the zoom adjusting lever 14 is turned to the wide angle side, thesecond support frame 20 is driven to the imaging unit 90 side by thefirst driving unit 50 according to the rotational angle and operationtime of the zoom adjusting lever 14, and the third support frame 30 isdriven to the imaging unit 90 side by the second driving unit 60.

Thus, when the second lens group G2 and the third lens group G3 movealong the second optical axis A2, the magnification ratio of the imagingoptical system increases.

(2) Operation of Aperture Unit

The drive lever 22 b is provided to the aperture unit 22 fixed to thesecond support frame 20, and the end of the drive lever 22 b is insertedinto the guide groove 72 a formed in the guide portion 72 of the mainbody frame 70. Accordingly, when the second support frame 20 moves alongthe second optical axis A2, as shown in FIGS. 15A and 15B, the drivelever 22 b is guided by the guide groove 72 a so as to rotate around thesecond optical axis A2. As a result, the aperture unit 22 changesbetween the stopped state shown in FIG. 15A and the open state shown inFIG. 15B, and the luminous energy is adjusted by the aperture unit 22 ofthe imaging optical system.

(3) Operation of Lens Driving Device

The fourth lens group G4 is driven by the lens driving device 40according to the amount of shake in the pitch and yaw directionsdetected by a shake detection sensor. More specifically, the amount ofdrive of the fourth lens group G4 in the pitch and yaw directions iscalculated by a control unit (not shown) on the basis of the shakeamount and positional information detected by a position sensor. Currentcorresponding to this drive amount is supplied to the first coil C11,the second coil C12, and the third coil C20. As a result, the fourthsupport frame 41 is driven in the pitch and yaw directions, and theoptical path is adjusted by the fourth lens group G4 so that there willbe no blurring of the image. This allows the position of the opticalimage of the subject to be adjusted according to the shaking of thedigital camera 1, so image blur can be corrected.

Features of Lens Barrel

Features of the lens barrel 3 are as follows.

(1)

With this lens barrel 3, the first lens group G1 has an overall negativerefractive power, which is advantageous in terms of achieving a widerangle, as compared to when the overall refractive power is positive, forexample.

In addition, since part of the first movement region M21 in which thesecond support frame 20 moves overlaps with the second movement regionM31 in which the third support frame 30 moves, the length of the lensbarrel 3 in a direction along the second optical axis A2 can be reduced.

Thus, this lens barrel 3 has a wider angle and is more compact.

(2)

Since the first driving unit 50 and the second driving unit 60 aredisposed flanking the second optical axis A2, when viewed in a directionalong the second optical axis A2, the overall lens barrel 3 is longer inthe X axis direction and shorter in the Y axis direction. This affords alens barrel 3 that is thinner.

(3)

When viewed in a direction along the second optical axis A2, the firstdriving unit 50 overlaps the yaw driving unit 82, and the second drivingunit 60 overlaps the pitch driving unit 81. Therefore, the pitch drivingunit 81 and the yaw driving unit 82 protrudes less in a direction (suchas the Y axis direction) that is different from the direction in whichthe first driving unit 50 and the second driving unit 60 are aligned.This means that the lens barrel 3 can be shorter in the Y axisdirection, affording a thinner lens barrel 3.

(4)

When viewed in a direction along the second optical axis A2, the firstouter end face 53 a of the first frame 53 of the first driving unit 50is disposed at substantially the same position in the X axis directionas the outer end face 47 a of the second yoke 47 of the yaw driving unit82. Therefore, it is less likely that there will be wasted space formedin the portion to the side of the lens barrel 3 on the side where thefirst driving unit 50 is disposed. This means that the various units canbe disposed more efficiently, and the lens barrel 3 can be even morecompact.

In particular, with this lens barrel 3, the first driving unit 50 andthe yaw driving unit 82 are disposed at the end of the camera main body2 on the X axis negative direction side, so layout efficiency is higher.

Also, if there is some extra space around the yaw driving unit 82, alarger driving unit can be employed as the yaw driving unit 82, whichmeans that the lens barrel 3 can be made smaller while achieving a morestable drive state for the fourth lens group G4.

The state here in which “the first outer end face 53 a is disposed atsubstantially the same position as the second outer end face 47 a of theyaw driving unit 82” encompasses not only a state in which the firstouter end face 53 a and the second outer end face 47 a are disposed atexactly the same position, but also a state in which the first outer endface 53 a and the second outer end face 47 a are shifted to the extentthat a reduction in the size of the lens barrel 3 can still be achieved.

(5)

Also, when viewed in a direction along the second optical axis A2, thethird outer end face 63 a of the second frame 63 of the second drivingunit 60 is disposed at substantially the same position as the fourthouter end face 46 a of the first yoke 46 of the pitch driving unit 81.Therefore, it is less likely that there will be wasted space formed inthe portion to the side of the lens barrel 3 on the side where the 60 isdisposed. This means that the various units can be disposed moreefficiently, and the lens barrel 3 can be even more compact.

Also, if there is some extra space around the pitch driving unit 81, alarger driving unit can be employed as the pitch driving unit 81, whichmeans that the lens barrel 3 can be made smaller while achieving a morestable drive state for the fourth lens group G4.

The state here in which “the third outer end face 63 a of the seconddriving unit 60 is disposed at substantially the same position as thefourth outer end face 46 a of the pitch driving unit 81” encompasses notonly a state in which the third outer end face 63 a and the fourth outerend face 46 a are disposed at exactly the same position, but also astate in which the third outer end face 63 a and the fourth outer endface 46 a are shifted to the extent that a reduction in the size of thelens barrel 3 can still be achieved.

(6)

The first drive motor 51 is disposed on the first lens group G1 side ofthe second support frame 20, and the second drive motor 61 is disposedon the first lens group G1 side of the third support frame 30.Therefore, the space around the first lens group G1 can be utilized moreeffectively, and the size of the lens barrel 3 can be reduced in adirection along the second optical axis A2.

In particular, when another fourth lens group G4 and the lens drivingdevice 40 are disposed on the opposite side of the third lens group G3from the first lens group G1, the lens driving device 40 will be lesslikely to be affected by changes in the magnetic field caused by thefirst drive motor 51 and the second drive motor 61, and drive of thelens driving device 40 will be less likely to be hindered.

(7)

Since the first drive motor 51 is disposed closer to the first lensgroup G1 than the second drive motor 61, the second lens group G2, whichis driven by the first drive motor 51, can be moved closer to the firstlens group G1. The space on the Z axis positive direction side of thesecond drive motor 61 can also be utilized more effectively.

(8)

When viewed in a direction along the second optical axis A2, part of themain body frame 70 overlaps the first support frame 10, so it is lesslikely that part of the light incident on the first lens group G1 from adirection along the second optical axis A2 will leak into the interiorfrom the gap formed between the first support frame 10 and the main bodyframe 70. That is, with this lens barrel 3, there is less of a decreasein optical performance. In particular, since the above-mentionedfeatures are obtained when viewed from the front face, it is even lesslikely that part of the light incident from the front face side (thatis, from the subject side) will leak into the interior from the gapformed between the first support frame 10 and the main body frame 70.

Also, since the first protrusion 12 a of the first support frame 10overlaps the Z axis positive direction end of the guide portion 72 ofthe main body frame 70 in the Y axis direction, the leakage of lightinto the interior of the barrel can be reduced with a simpleconfiguration.

Furthermore, since the second protrusion 12 b of the first support frame10 is inserted into the recess 71 a of the forward plate 71, the end ofthe forward plate 71 can be covered by the second protrusion 12 b, andthis further reduces the entrance of stray light.

(9)

With the lens driving device 40, since the electrical board 48 (whichfunctions as a driven member) is disposed on the first lens group G1side of the fourth support frame 41, the positions of the pitch drivingunit 81 and the yaw driving unit 82 move to the first lens group G1 morethan when the disposition is on the opposite side from the first lensgroup G1 side. Accordingly, space can be ensured at both ends in the Xaxis direction and on the Z axis negative direction side of the lensdriving device 40. This space can be effectively utilized in the fixingof the lens barrel 3 to the camera main body 2. For example, screws orother such fixing members can be disposed in this space. This improvesthe layout efficiency of the lens driving device 40.

Also, the positions of the pitch driving unit 81 and the yaw drivingunit 82 are closer to the third support frame 30, so the overall layoutefficiency of the lens barrel 3 is also improved.

(10)

Since the aperture unit 22 and the shutter unit 29 are fixed to thesecond support frame 20, this means that the second support frame 20,the aperture unit 22, and the shutter unit 29 can share the firstdriving unit 50, so there is no need to provide a separate drivingdevice for the aperture unit 22 and the shutter unit 29. This allows thelens barrel 3 to have a simpler configuration and lowers themanufacturing cost.

(11)

Since the aperture unit 22 is disposed on the first lens group G1 sideof the second support frame 20, the first lens group G1 (andparticularly the prism PR) can be smaller, and the lens barrel 3 can bemore compact.

(12)

Since the shutter unit 29 is disposed on the opposite side of the secondsupport frame 20 from the first lens group G1 side, the second lensgroup G2 can move closer to the first lens group G1. This affords abetter variable power ratio, and allows a lens barrel 3 that is smallerand higher in power to be obtained.

(13)

Since the shutter drive motor 27 is disposed more to the first lensgroup G1 side than the shutter mechanism 29 a in a direction along thesecond optical axis A2, this prevents the shutter drive motor 27 frominterfering with the lens driving device 40. In other words, the spaceon the first lens group G1 side of the shutter mechanism 29 a can beused more effectively. This allows the lens barrel 3 to be more compact.

(14)

Since the main body frame 70 has the guide portion 72, when the secondsupport frame 20 moves linearly in a direction along the second opticalaxis A2, the guide groove 72 a of the guide portion 72 causes the drivelever 22 b to rotate around the second optical axis A2, and thisrotational force acts on the aperture mechanism 22 a. Therefore, thefirst driving unit 50 can be utilized to open and close the apertureunit 22, so a driving device for the aperture unit 22 can be omitted.This simplifies the configuration of the lens barrel 3, allows it to bemore compact, and lowers its manufacturing cost.

(15)

Since at least part of the convex face L4 a of the fourth lens L4 isdisposed inside the opening of the aperture unit 22, the aperture unit22 can be disposed closer to the fourth lens L4. This shortens theoverall length of the fourth lens L4 and the aperture unit 22, andreduces the size of the lens barrel 3. This also allows the second lensgroup G2 to move closer to the first lens group G1. As a result, ahigher magnification ratio can be obtained, and the lens barrel 3 willbe smaller and have higher power.

(16)

When viewed in a direction along the second optical axis A2, the shutterdrive motor 27 and the filter drive motor 28 are disposed flanking thesecond optical axis A2, so the shutter unit 29 is longer in the X axisdirection, and the shutter unit 29 is shorter in the Y axis direction.This means that a thinner lens barrel 3 can be obtained.

(17)

When viewed in a direction along the second optical axis A2, the firstguide shaft 59 and the second guide shaft 69 are disposed flanking thesecond optical axis A2, so the lens barrel 3 is longer in the X axisdirection, but shorter in the Y axis direction. This means that athinner lens barrel 3 can be obtained.

(18)

When viewed in a direction along the second optical axis A2, the firstguide shaft 59 is disposed closer to the filter drive motor 28, and thesecond guide shaft 69 is disposed closer to the shutter drive motor 27.Therefore, the lens barrel 3 is longer in the X axis direction, butshorter in the Y axis direction. This means that a thinner lens barrel 3can be obtained.

(19)

The shutter drive motor 27 and the second guide shaft 69 are disposed onone side (the X axis positive direction side) with respect to a planethat includes the first optical axis A1 and the second optical axis A2,and the filter drive motor 28 and the first guide shaft 59 are disposedon the other side (the X axis negative direction side) with respect tothe plane that includes the first optical axis A1 and the second opticalaxis A2. When viewed in a direction along the first optical axis A1, andfrom the side (Y axis positive direction side) where the shutter drivemotor 27 is disposed in front of the second guide shaft 69, the firstguide shaft 59 is disposed in front (on the Y axis positive directionside) of the filter drive motor 28. This means that the lens barrel 3 isshorter in the Y axis direction.

The distance between the first guide shaft 59 and the second guide shaft69 can be increased within the X axial range of the lens barrel 3. Thismeans that the lens barrel 3 can be thinner and more compact. Also, thesecond support frame 20 and the third support frame 30 can be smoothlyguided in a direction along the second optical axis A2.

(20)

With a conventional method for bonding lenses, for example, a secondlens is flanked by a support frame and a first lens, and the first lensis adhesively fixed to the support frame. In this case, since the secondlens is not bonded, it is not completely fixed, and there is the riskthat the second lens will move with respect to the support frame.

However, as shown in FIGS. 13, 14A, and 14B, with this lens barrel 3,since two kinds of groove, the first bonding grooves 21 b and the secondbonding grooves 21 c, are formed in the second support frame 20, thefifth lens L5 and the sixth lens L6 can be individually bonded and fixedto the second support frame 20. This prevents a shift in the relativepositions of the fifth lens L5 and the sixth lens L6, and a lens supportstructure that minimizes a decrease in optical performance can beachieved with a simple configuration.

Other Embodiments

The lens barrel according to the present invention is not limited to theembodiment given above, and various changes and modifications arepossible without departing from the gist of the present invention.

(1)

The lens barrel 3 discussed above can be applied not only to a digitalcamera, but also to a mobile telephone, a PDA (personal digitalassistant), and other such imaging devices.

(2)

In the above embodiment, the lens driving device 40 has the pitchdriving unit 81 and the yaw driving unit 82 disposed at differentpositions, but it is also possible for these driving devices to bedisposed integrally. In this case, when viewed in a direction along thesecond optical axis A2, a thinner lens barrel 3 can be obtained if thefirst driving unit 50 or the second driving unit 60 overlaps thisintegrated driving device.

Also, the pitch driving unit 81 and the yaw driving unit 82 may eachinclude a plurality of driving devices.

(3)

The first driving unit 50 and the second driving unit 60 may be otherkinds of driving devices, such as an electromagnetic actuator.

(4)

In the above embodiment, the first guide shaft 59 and the filter drivemotor 28 are disposed on the X axis negative direction side of the firstboundary E1, and the second guide shaft 69 and th shutter drive motor 27are disposed on the X axis positive direction side of the first boundaryE1, but these layouts may be reversed in the X axis direction. That is,the first guide shaft 59 and the filter drive motor 28 may be disposedon the X axis positive direction side of the first boundary E1, and thesecond guide shaft 69 and the shutter drive motor 27 may be disposed onthe X axis negative direction side of the first boundary E1.

Also, the layout of the first guide shaft 59 and the second guide shaft69 may be reversed in the X axis direction. That is, the second guideshaft 69 and the filter drive motor 28 may be disposed on one side ofthe first boundary E1 (the X axis positive or negative direction side),and the first guide shaft 59 and the shutter drive motor 27 may bedisposed on the other side of the first boundary E1 (the opposite sidefrom the side where the second guide shaft 69 is disposed).

(5)

Also, in the above embodiment, the first guide shaft 59 and the shutterdrive motor 27 are disposed on the Y axis positive direction side of thesecond boundary E2, and the second guide shaft 69 and the filter drivemotor 28 are disposed on the Y axis negative direction side of thesecond boundary E2, but the layout of these may be reversed in the Yaxis direction. That is, the first guide shaft 59 and the shutter drivemotor 27 may be disposed on the Y axis negative direction side of thesecond boundary E2, and the second guide shaft 69 and the filter drivemotor 28 may be disposed on the Y axis positive direction side of thesecond boundary E2.

Also, the first guide shaft 59 and the second guide shaft 69 may bereversed. That is, the second guide shaft 69 and the shutter drive motor27 may be disposed on one side of the second boundary E2 (the Y axispositive or negative direction side), and the first guide shaft 59 andthe filter drive motor 28 may be disposed on the other side of thesecond boundary E2 (the opposite side from the side where the secondguide shaft 69 is disposed).

Additions

The technology included in the above embodiment will be described fromother standpoints.

(1)

An imaging optical system usually has a plurality of lens groups.Whether the refractive power of the first lens group that takes in lightfrom a subject is positive or negative affects how small the lens barrelcan be made, the magnification ratio of the optical system, and soforth.

For instance, if the first lens group has a positive refractive power(in the case of an imaging optical system that is called a positive leadtype), it is easy to attain a high magnification ratio, but the quantityof lenses is greater, which is disadvantageous in terms of making thelens barrel smaller.

On the other hand, if the first lens group has a negative refractivepower (in the case of an imaging optical system that is called anegative lead type), it is more difficult to attain a high magnificationratio than with a positive lead type, but there are fewer lenses, whichis advantageous in terms of making the lens barrel smaller, and is alsosuited to achieving a wider angle.

Thus, when the first lens group has a negative refractive power, it iseasier to obtain a lens barrel that is compact and has a wider angle.

However, with a negative lead type of imaging optical system, a secondlens group and a third lens group having positive refractive power mustbe provided behind the first lens group, and depending on the layout ofthe drive mechanisms for the second and third lens groups, efforts toreduce the size of the lens barrel may be hampered.

It is a first object is to provide a lens barrel that has a wider angleand is more compact.

Also, in the fixing of a first lens group including a bending opticalelement, it is possible for the first lens group to be fixed to asupport frame, and the support frame fixed to the camera housing or themain body frame of the lens barrel.

However, when a gap is formed between this support frame and the mainbody frame, for example, light may leak into the imaging optical systemfrom the outside, which diminishes the optical performance.

It is a second object to minimize the decrease in optical performance ina lens barrel having a bending optical element.

Furthermore, a conventional imaging device is sometimes equipped with animage blur correction device for correcting blurring of images caused bymovement of the camera main body. For instance, an image blur correctiondevice may have a base plate, a yaw frame that is supported movably inthe yaw direction by the base plate, a pitch frame that is supportedmovably in the pitch direction by the yaw frame, and a drive device fordriving the pitch frame. A correcting lens and an electrical board arefixed to the pitch frame. The drive device has a coil provided to theelectrical board, a yoke fixed to the base plate, and a magnet fixed tothe yoke.

With this image blur correction device, since the electrical board isfixed on the yaw frame side (the imaging element side) of the pitchframe, the positions of the yoke and magnet move to the imaging deviceside along with the electrical board, and this reduces the efficiency ofthe drive device layout. As a result, efforts to reduce the size of thedevice that drives the correcting lens or other such optical elementsare hampered.

It is a third object to provide an optical element drive device that ismore compact.

A lens barrel according to Addition 1 is a lens barrel for forming anoptical image of a subject, and includes a first lens group, a secondlens group, a third lens group, a first support frame, a first supportmechanism, a second support mechanism, a first driving unit, and asecond driving unit. The first lens group takes in a light beam comingfrom the subject along a first optical axis, and has a bending opticalelement with which the light beam incident along the first optical axisis reflected in a direction along a second optical axis that intersectsthe first optical axis, and has an overall negative refractive power.The second lens group takes in the light beam that has passed throughthe first lens group. The third lens group takes in the light beam thathas passed through the second lens group. The first support framesupports the first lens group. The first support mechanism supports thesecond lens group so that it can move along the second optical axis withrespect to the first lens group, and has a second support frame forsupporting the second lens group. The second support mechanism supportsthe third lens group so that it can move along the second optical axiswith respect to the first lens group, and has a third support frame forsupporting the third lens group. The first driving unit imparts a driveforce to the second support frame so that the second lens group moves ina direction along the second optical axis. The second driving unit thatimparts a drive force to the third support frame so that the third lensgroup moves in a direction along the second optical axis. At least partof the region in which the second support frame moves overlaps theregion in which the third support frame moves.

With this lens barrel, the first lens group has an overall negativerefractive power, which is more advantageous in terms of obtaining awide angle.

In addition, since at least part of the region in which the secondsupport frame moves overlaps the region in which the third support framemoves, the size of the lens barrel in a direction along the secondoptical axis can be reduced.

Thus, a wider angle and a smaller size can be obtained with this lensbarrel.

A lens barrel according to Addition 2 is the lens barrel of Addition 1,wherein the first and second driving units are disposed flanking thesecond optical axis when viewed in a direction along the second opticalaxis.

A lens barrel according to Addition 3 is the lens barrel of Addition 1or 2, further including a fourth lens group that takes in the light beamthat has passed through the third lens group, a third support mechanismthat supports the fourth lens group so that it can move over a planethat is perpendicular to the second optical axis with respect to thefirst lens group, and that has a fourth support frame for supporting thefourth lens group, and a third driving unit that imparts a drive forceto the fourth support frame so that the fourth lens group can move withrespect to the first lens group. At least one of the first and seconddriving units overlaps the third driving unit when viewed in a directionalong the second optical axis.

The third driving unit here may be made up of a plurality of units, inwhich case at least one unit may overlap the first and second drivingunits. For instance, the third driving unit may have a unit for drivingthe fourth support frame in a first direction that is perpendicular tothe second optical axis, and a unit for driving the fourth support framein a second direction that is perpendicular to the second optical axis.

A lens barrel according to Addition 4 is the lens barrel of Addition 3,wherein the third driving unit has a first direction driving unit fordriving the fourth support frame in a first direction that isperpendicular to the second optical axis, and a second direction drivingunit for driving the fourth support frame in a second direction that isperpendicular to the second optical axis. At least part of the firstdriving unit overlaps the first direction driving unit when viewed in adirection along the second optical axis. At least part of the seconddriving unit overlaps the second direction driving unit when viewed in adirection along the second optical axis.

The first and second driving units here may each be made up of not justone, but a plurality of units.

A lens barrel according to Addition 5 is the lens barrel of Addition 4,wherein, when viewed in a direction along the second optical axis, theouter end of the first driving unit on the opposite side from the secondoptical axis is disposed at substantially the same position as the outerend of the first direction driving unit on the opposite side from thesecond optical axis.

The phrase “the outer end of the first driving unit is disposed atsubstantially the same position as the outer end of the first directiondriving unit” here encompasses not only a case in which the two outerends are disposed at exactly the same position, but also a case in whichthe two outer ends are shifted to the extent that a reduction in thesize of the lens barrel can still be achieved.

A lens barrel according to Addition 6 is the lens barrel of Addition 4or 5, wherein, when viewed in a direction along the second optical axis,the outer end of the second driving unit on the opposite side from thesecond optical axis is disposed at substantially the same position asthe outer end of the second direction driving unit on the opposite sidefrom the second optical axis.

The phrase “the outer end of the second driving unit is disposed atsubstantially the same position as the outer end of the second directiondriving unit” here encompasses not only a case in which the two outerends are disposed at exactly the same position, but also a case in whichthe two outer ends are shifted to the extent that a reduction in thesize of the lens barrel can still be achieved.

A lens barrel according to Addition 7 is the lens barrel of any one ofAdditions 1 to 6, wherein the first driving unit has a first drive shaftthat meshes with the second support frame, and a first drive motor thatimparts a rotational force to the first drive shaft. The second drivingunit has a second drive shaft that meshes with the third support frame,and a second drive motor that imparts a rotational force to the seconddrive shaft. The first drive motor is disposed on the first lens groupside of the second support frame. The second drive motor is disposed onthe first lens group side of the third support frame.

A lens barrel according to Addition 8 is the lens barrel of Addition 7,wherein the first drive motor is disposed closer to the first lens groupthan the second drive motor in a direction along the second opticalaxis.

A lens barrel according to Addition 9 is the lens barrel of any one ofAdditions 1 to 8, further including a main body frame to which the firstsupport frame is fixed, and for holding the second lens group. Part ofthe main body frame overlaps the first support frame when viewed in adirection along the first optical axis.

A lens barrel according to Addition 10 is the lens barrel of Addition 9,wherein the first support frame has a first protrusion that protrudes ina direction along the second optical axis. The first protrusion overlapsthe main body frame when viewed in a direction along the first opticalaxis.

A lens barrel according to Addition 11 is the lens barrel of Addition 3,wherein the fourth support frame has a fourth support frame main bodythat supports the fourth lens group, and a driven member that is fixedon the first lens group side of the fourth support frame main body andreceives the drive force generated by the third driving unit.

A lens barrel according to Addition 12 forms an optical image of asubject, and includes a first lens group that takes in a light beamcoming from the subject along a first optical axis, and that has abending optical element with which the light beam incident along thefirst optical axis is reflected in a direction along a second opticalaxis that intersects the first optical axis, a second lens group thattakes in the light beam that has passed through the first lens group, afirst support frame for supporting the first lens group, and a main bodyframe to which the first support frame is fixed, and for holding thesecond lens group, and which overlaps part of the first support framewhen viewed in a direction along the first optical axis.

With this lens barrel, since the first support frame overlaps part ofthe main body frame when viewed in a direction along the first opticalaxis, there is less leakage of light into the interior of the barrelfrom a gap formed between the first support frame and the main bodyframe, so the decrease in optical performance can be minimized.

A lens barrel according to a Addition 13 is the lens barrel according toAddition 12, wherein the first support frame has a first protrusion thatprotrudes in a direction along the second optical axis. The firstprotrusion overlaps the main body frame when viewed in a direction alongthe first optical axis.

An optical element drive device according to Addition 14 drives a lensgroup within a plane that is perpendicular to the optical axis, andincludes a support frame main body that supports the lens group, asupport mechanism that supports the support frame main body so that itcan move within a plane that is perpendicular to the optical axis, adriven member that is fixed to the support frame main body and disposedon the incident side of the support frame main body in a direction alongthe optical axis, and a driving unit that imparts a drive force to thedriven member.

With this optical element drive device, since a driven member thatreceives the drive force generated by a driving unit is disposed on thefirst lens group side of a support frame main body, the position of thedriving unit moves more to the first lens group side than when thedriven member is disposed on the opposite side of the support frame mainbody from the first lens group side. Therefore, with this opticalelement drive device, the position of the driving unit is even closer toother configurations, the layout efficiency is further improved, and areduction in size can be achieved.

(2)

A conventional lens barrel is provided with a shutter unit for openingup and blocking off the optical path. This shutter unit has a shuttermechanism, a shutter drive motor for opening and closing the shuttermechanism, a filter provided so as to be capable of being inserting intoand retracted from the optical path, and a filter drive motor fordriving the filter. The shutter drive motor and the filter drive motorare disposed close to the shutter mechanism and the filter.

However, depending on how these drive motors are disposed, they mayhinder efforts to reduce the size of the lens barrel.

It is an object to obtain a smaller lens barrel.

A lens barrel according to Addition 15 is a lens barrel for forming anoptical image of a subject, including a first lens group, a second lensgroup, a third lens group, a first support frame, a first supportmechanism, and an optical path blocking unit. The first lens group takesin a light beam coming from the subject along a first optical axis, andhas a bending optical element with which the light beam incident alongthe first optical axis is reflected in a direction along a secondoptical axis that intersects the first optical axis. The second lensgroup takes in the light beam that has passed through the first lensgroup. The third lens group takes in the light beam that has passedthrough the second lens group. The first support frame supports thefirst lens group. The first support mechanism supports the second lensgroup to be movable along the second optical axis with respect to thefirst lens group, and has a second support frame for supporting thesecond lens group. The optical path blocking unit has an optical pathblocking mechanism provided to be capable of opening and blocking offthe optical path along the second optical axis, a blocking drive motorthat drives the optical path blocking mechanism, an optical elementprovided to be capable of being inserted into the optical path along thesecond optical axis and being retracted from the optical path, and anelement drive motor that drives the optical element. The blocking drivemotor and the element drive motor are disposed flanking the secondoptical axis when viewed in a direction along the second optical axis.

With this lens barrel, since the blocking drive motor and the elementdrive motor are disposed flanking the second optical axis when viewed ina direction along the second optical axis., the optical path blockingunit is longer in one direction, but the length is shorter in the otherdirection of the optical path blocking unit. This affords a more compactlens barrel.

A lens barrel according to Addition 16 is the lens barrel of Addition15, further including a second support mechanism that supports the thirdlens group to be movable along the second optical axis with respect tothe first lens group, and has a third support frame supporting the thirdlens group and a second guide shaft arranged to guide the third supportframe in a direction along the second optical axis. The first supportmechanism has a first guide shaft arranged to guide the second supportframe in a direction along the second optical axis. The first and secondguide shafts are disposed flanking the second optical axis when viewedin a direction along the second optical axis.

A lens barrel according to Addition 17 is the lens barrel of Addition16, wherein the first guide shaft is disposed closer to either theblocking drive motor or the element drive motor when viewed in adirection along the second optical axis, and the second guide shaft isdisposed closer to the other of the blocking drive motor and the elementdrive motor.

A lens barrel according to Addition 18 is the lens barrel of Addition16, wherein the blocking drive motor and the second guide shaft aredisposed on one side with respect to a face including the first opticalaxis and the second optical axis. The element drive motor and the firstguide shaft are disposed on the other side with respect to a faceincluding the first optical axis and the second optical axis. The firstguide shaft is disposed in front of the element drive motor when viewedfrom the side on which the blocking drive motor is disposed in front ofthe second guide shaft and in a direction along the first optical axis.

A lens barrel according to Addition 19 is the lens barrel of Addition16, wherein the blocking drive motor and the first guide shaft aredisposed on one side with respect to a face including the first opticalaxis and the second optical axis. The element drive motor and the secondguide shaft are disposed on the other side with respect to a faceincluding the first optical axis and the second optical axis. The secondguide shaft is disposed in front of the element drive motor when viewedfrom the side on which the blocking drive motor is disposed in front ofthe first guide shaft and in a direction along the first optical axis.

INDUSTRIAL APPLICABILITY

Manufacturing costs can be reduced with the lens barrel according to thepresent invention, so the present invention is useful in the field ofcameras, as well as the field of portable telephones and the like thathave a camera function.

1.-9. (canceled)
 10. A lens barrel for forming an optical image of asubject, comprising: a first lens group configured to receive a lightbeam coming from the subject along a first optical axis, the first lensgroup having a bending optical element configured to reflect a lightbeam incident along the first optical axis along a second optical axisthat intersects the first optical axis; a second lens group configuredto receive a light beam passing through the first lens group; a thirdlens group configured to receive a light beam passing through the secondlens group; a first support frame supporting the first lens group; afirst support mechanism supporting the second lens group movably withrespect to the first lens group along the second optical axis, andhaving a second support frame supporting the second lens group; a firstdriving unit configured to impart a drive force to the second supportframe so that the second lens group moves along the second optical axis;a luminous energy adjusting unit configured to adjust the amount oflight passing through the second lens group or the amount of lightemitted from the second lens group, and fixed to the second supportframe; and an optical path blocking unit configured to open and blockthe optical path along the second optical axis, and fixed to the secondsupport frame.
 11. The lens barrel according to claim 10, wherein theluminous energy adjusting unit is disposed on the first lens group sideof the second support frame along the second optical axis.
 12. The lensbarrel according to claim 11, wherein the optical path blocking unit isdisposed on the opposite side of the second support frame from the firstlens group side along the second optical axis.
 13. The lens barrelaccording to claim 12, wherein the optical path blocking unit has anoptical path blocking mechanism arranged to open and block the opticalpath along the second optical axis, and a blocking drive motorconfigured to drive the optical path blocking mechanism, and theblocking drive motor is disposed more to the first lens group side thanthe optical path blocking mechanism along the second optical axis. 14.The lens barrel according to claim 13, further comprising a main bodyframe to which the first support mechanism is provided, wherein theluminous energy adjusting unit has a luminous energy adjusting mechanismwith which the aperture can be adjusted by utilizing a rotational forcearound the second optical axis, and a transmission member configured totransmit the rotational force to the luminous energy adjustingmechanism, and the main body frame has a guide portion arranged toconvert the linear motion of the second support frame along the secondoptical axis with respect to the main body frame into rotary motion ofthe transmission member around the second optical axis.
 15. The lensbarrel according to claim 14, wherein the transmission member extendsfrom the luminous energy adjusting mechanism in a directionperpendicular to the second optical axis, and the guide portion has aguide groove into which the transmission member is inserted, and whichis inclined with respect to a direction along the second optical axis.16. The lens barrel according to claim 15, wherein the first lens grouphas an overall negative refractive power.
 17. The lens barrel accordingto claim 10, wherein the optical path blocking unit is disposed on theopposite side of the second support frame from the first lens group sidealong the second optical axis.
 18. The lens barrel according to claim17, wherein the optical path blocking unit has an optical path blockingmechanism arranged to open and block the optical path along the secondoptical axis, and a blocking drive motor configured to drive the opticalpath blocking mechanism, and the blocking drive motor is disposed moreto the first lens group side than the optical path blocking mechanismalong the second optical axis.
 19. The lens barrel according to claim18, further comprising a main body frame to which the first supportmechanism is provided, wherein the luminous energy adjusting unit has aluminous energy adjusting mechanism with which the aperture can beadjusted by utilizing a rotational force around the second optical axis,and a transmission member configured to transmit the rotational force tothe luminous energy adjusting mechanism, and the main body frame has aguide portion arranged to convert the linear motion of the secondsupport frame along the second optical axis with respect to the mainbody frame into rotary motion of the transmission member around thesecond optical axis.
 20. The lens barrel according to claim 19, whereinthe transmission member extends from the luminous energy adjustingmechanism in a direction perpendicular to the second optical axis, andthe guide portion has a guide groove into which the transmission memberis inserted, and which is inclined with respect to a direction along thesecond optical axis.
 21. The lens barrel according to claim 20, whereinthe first lens group has an overall negative refractive power.
 22. Thelens barrel according to claim 10, wherein the optical path blockingunit has an optical path blocking mechanism arranged to open and blockthe optical path along the second optical axis, and a blocking drivemotor configured to drive the optical path blocking mechanism, and theblocking drive motor is disposed more to the first lens group side thanthe optical path blocking mechanism along the second optical axis. 23.The lens barrel according to claim 22, further comprising a main bodyframe to which the first support mechanism is provided, wherein theluminous energy adjusting unit has a luminous energy adjusting mechanismwith which the aperture can be adjusted by utilizing a rotational forcearound the second optical axis, and a transmission member configured totransmit the rotational force to the luminous energy adjustingmechanism, and the main body frame has a guide portion arranged toconvert the linear motion of the second support frame along the secondoptical axis with respect to the main body frame into rotary motion ofthe transmission member around the second optical axis.
 24. The lensbarrel according to claim 23, wherein the transmission member extendsfrom the luminous energy adjusting mechanism in a directionperpendicular to the second optical axis, and the guide portion has aguide groove into which the transmission member is inserted, and whichis inclined with respect to a direction along the second optical axis.25. The lens barrel according to claim 24, wherein the first lens grouphas an overall negative refractive power.
 26. The lens barrel accordingto claim 10, further comprising a main body frame to which the firstsupport mechanism is provided, wherein the luminous energy adjustingunit has a luminous energy adjusting mechanism with which the aperturecan be adjusted by utilizing a rotational force around the secondoptical axis, and a transmission member configured to transmit therotational force to the luminous energy adjusting mechanism, and themain body frame has a guide portion arranged to convert the linearmotion of the second support frame along the second optical axis withrespect to the main body frame into rotary motion of the transmissionmember around the second optical axis.
 27. The lens barrel according toclaim 26, wherein the transmission member extends from the luminousenergy adjusting mechanism in a direction perpendicular to the secondoptical axis, and the guide portion has a guide groove into which thetransmission member is inserted, and which is inclined with respect to adirection along the second optical axis.
 28. A lens support structure,comprising: a lens having a convex face; a lens support frame supportingthe lens; and an aperture member fixed to the lens support frame,wherein at least part of the convex face of the lens is disposed withinthe opening of the aperture member along the optical axis of the lens.29. The lens support structure according to claim 28, wherein theaperture member is provided so that a position of the aperture memberwith respect to the lens does not change.